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Diffstat (limited to 'vendor/github.com/google/gops/internal/obj/link.go')
| -rw-r--r-- | vendor/github.com/google/gops/internal/obj/link.go | 974 |
1 files changed, 974 insertions, 0 deletions
diff --git a/vendor/github.com/google/gops/internal/obj/link.go b/vendor/github.com/google/gops/internal/obj/link.go new file mode 100644 index 00000000..e2530615 --- /dev/null +++ b/vendor/github.com/google/gops/internal/obj/link.go @@ -0,0 +1,974 @@ +// Derived from Inferno utils/6l/l.h and related files. +// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/l.h +// +// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. +// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net) +// Portions Copyright © 1997-1999 Vita Nuova Limited +// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com) +// Portions Copyright © 2004,2006 Bruce Ellis +// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net) +// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others +// Portions Copyright © 2009 The Go Authors. All rights reserved. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +package obj + +import ( + "bufio" + "fmt" + + "github.com/google/gops/internal/sys" +) + +// An Addr is an argument to an instruction. +// The general forms and their encodings are: +// +// sym±offset(symkind)(reg)(index*scale) +// Memory reference at address &sym(symkind) + offset + reg + index*scale. +// Any of sym(symkind), ±offset, (reg), (index*scale), and *scale can be omitted. +// If (reg) and *scale are both omitted, the resulting expression (index) is parsed as (reg). +// To force a parsing as index*scale, write (index*1). +// Encoding: +// type = TYPE_MEM +// name = symkind (NAME_AUTO, ...) or 0 (NAME_NONE) +// sym = sym +// offset = ±offset +// reg = reg (REG_*) +// index = index (REG_*) +// scale = scale (1, 2, 4, 8) +// +// $<mem> +// Effective address of memory reference <mem>, defined above. +// Encoding: same as memory reference, but type = TYPE_ADDR. +// +// $<±integer value> +// This is a special case of $<mem>, in which only ±offset is present. +// It has a separate type for easy recognition. +// Encoding: +// type = TYPE_CONST +// offset = ±integer value +// +// *<mem> +// Indirect reference through memory reference <mem>, defined above. +// Only used on x86 for CALL/JMP *sym(SB), which calls/jumps to a function +// pointer stored in the data word sym(SB), not a function named sym(SB). +// Encoding: same as above, but type = TYPE_INDIR. +// +// $*$<mem> +// No longer used. +// On machines with actual SB registers, $*$<mem> forced the +// instruction encoding to use a full 32-bit constant, never a +// reference relative to SB. +// +// $<floating point literal> +// Floating point constant value. +// Encoding: +// type = TYPE_FCONST +// val = floating point value +// +// $<string literal, up to 8 chars> +// String literal value (raw bytes used for DATA instruction). +// Encoding: +// type = TYPE_SCONST +// val = string +// +// <register name> +// Any register: integer, floating point, control, segment, and so on. +// If looking for specific register kind, must check type and reg value range. +// Encoding: +// type = TYPE_REG +// reg = reg (REG_*) +// +// x(PC) +// Encoding: +// type = TYPE_BRANCH +// val = Prog* reference OR ELSE offset = target pc (branch takes priority) +// +// $±x-±y +// Final argument to TEXT, specifying local frame size x and argument size y. +// In this form, x and y are integer literals only, not arbitrary expressions. +// This avoids parsing ambiguities due to the use of - as a separator. +// The ± are optional. +// If the final argument to TEXT omits the -±y, the encoding should still +// use TYPE_TEXTSIZE (not TYPE_CONST), with u.argsize = ArgsSizeUnknown. +// Encoding: +// type = TYPE_TEXTSIZE +// offset = x +// val = int32(y) +// +// reg<<shift, reg>>shift, reg->shift, reg@>shift +// Shifted register value, for ARM and ARM64. +// In this form, reg must be a register and shift can be a register or an integer constant. +// Encoding: +// type = TYPE_SHIFT +// On ARM: +// offset = (reg&15) | shifttype<<5 | count +// shifttype = 0, 1, 2, 3 for <<, >>, ->, @> +// count = (reg&15)<<8 | 1<<4 for a register shift count, (n&31)<<7 for an integer constant. +// On ARM64: +// offset = (reg&31)<<16 | shifttype<<22 | (count&63)<<10 +// shifttype = 0, 1, 2 for <<, >>, -> +// +// (reg, reg) +// A destination register pair. When used as the last argument of an instruction, +// this form makes clear that both registers are destinations. +// Encoding: +// type = TYPE_REGREG +// reg = first register +// offset = second register +// +// [reg, reg, reg-reg] +// Register list for ARM. +// Encoding: +// type = TYPE_REGLIST +// offset = bit mask of registers in list; R0 is low bit. +// +// reg, reg +// Register pair for ARM. +// TYPE_REGREG2 +// +// (reg+reg) +// Register pair for PPC64. +// Encoding: +// type = TYPE_MEM +// reg = first register +// index = second register +// scale = 1 +// +type Addr struct { + Reg int16 + Index int16 + Scale int16 // Sometimes holds a register. + Type AddrType + Name int8 + Class int8 + Offset int64 + Sym *LSym + + // argument value: + // for TYPE_SCONST, a string + // for TYPE_FCONST, a float64 + // for TYPE_BRANCH, a *Prog (optional) + // for TYPE_TEXTSIZE, an int32 (optional) + Val interface{} + + Node interface{} // for use by compiler +} + +type AddrType uint8 + +const ( + NAME_NONE = 0 + iota + NAME_EXTERN + NAME_STATIC + NAME_AUTO + NAME_PARAM + // A reference to name@GOT(SB) is a reference to the entry in the global offset + // table for 'name'. + NAME_GOTREF +) + +const ( + TYPE_NONE AddrType = 0 + + TYPE_BRANCH AddrType = 5 + iota + TYPE_TEXTSIZE + TYPE_MEM + TYPE_CONST + TYPE_FCONST + TYPE_SCONST + TYPE_REG + TYPE_ADDR + TYPE_SHIFT + TYPE_REGREG + TYPE_REGREG2 + TYPE_INDIR + TYPE_REGLIST +) + +// Prog describes a single machine instruction. +// +// The general instruction form is: +// +// As.Scond From, Reg, From3, To, RegTo2 +// +// where As is an opcode and the others are arguments: +// From, Reg, From3 are sources, and To, RegTo2 are destinations. +// Usually, not all arguments are present. +// For example, MOVL R1, R2 encodes using only As=MOVL, From=R1, To=R2. +// The Scond field holds additional condition bits for systems (like arm) +// that have generalized conditional execution. +// +// Jump instructions use the Pcond field to point to the target instruction, +// which must be in the same linked list as the jump instruction. +// +// The Progs for a given function are arranged in a list linked through the Link field. +// +// Each Prog is charged to a specific source line in the debug information, +// specified by Lineno, an index into the line history (see LineHist). +// Every Prog has a Ctxt field that defines various context, including the current LineHist. +// Progs should be allocated using ctxt.NewProg(), not new(Prog). +// +// The other fields not yet mentioned are for use by the back ends and should +// be left zeroed by creators of Prog lists. +type Prog struct { + Ctxt *Link // linker context + Link *Prog // next Prog in linked list + From Addr // first source operand + From3 *Addr // third source operand (second is Reg below) + To Addr // destination operand (second is RegTo2 below) + Pcond *Prog // target of conditional jump + Opt interface{} // available to optimization passes to hold per-Prog state + Forwd *Prog // for x86 back end + Rel *Prog // for x86, arm back ends + Pc int64 // for back ends or assembler: virtual or actual program counter, depending on phase + Lineno int32 // line number of this instruction + Spadj int32 // effect of instruction on stack pointer (increment or decrement amount) + As As // assembler opcode + Reg int16 // 2nd source operand + RegTo2 int16 // 2nd destination operand + Mark uint16 // bitmask of arch-specific items + Optab uint16 // arch-specific opcode index + Scond uint8 // condition bits for conditional instruction (e.g., on ARM) + Back uint8 // for x86 back end: backwards branch state + Ft uint8 // for x86 back end: type index of Prog.From + Tt uint8 // for x86 back end: type index of Prog.To + Isize uint8 // for x86 back end: size of the instruction in bytes + Mode int8 // for x86 back end: 32- or 64-bit mode +} + +// From3Type returns From3.Type, or TYPE_NONE when From3 is nil. +func (p *Prog) From3Type() AddrType { + if p.From3 == nil { + return TYPE_NONE + } + return p.From3.Type +} + +// From3Offset returns From3.Offset, or 0 when From3 is nil. +func (p *Prog) From3Offset() int64 { + if p.From3 == nil { + return 0 + } + return p.From3.Offset +} + +// An As denotes an assembler opcode. +// There are some portable opcodes, declared here in package obj, +// that are common to all architectures. +// However, the majority of opcodes are arch-specific +// and are declared in their respective architecture's subpackage. +type As int16 + +// These are the portable opcodes. +const ( + AXXX As = iota + ACALL + ADUFFCOPY + ADUFFZERO + AEND + AFUNCDATA + AJMP + ANOP + APCDATA + ARET + ATEXT + ATYPE + AUNDEF + AUSEFIELD + AVARDEF + AVARKILL + AVARLIVE + A_ARCHSPECIFIC +) + +// Each architecture is allotted a distinct subspace of opcode values +// for declaring its arch-specific opcodes. +// Within this subspace, the first arch-specific opcode should be +// at offset A_ARCHSPECIFIC. +// +// Subspaces are aligned to a power of two so opcodes can be masked +// with AMask and used as compact array indices. +const ( + ABase386 = (1 + iota) << 10 + ABaseARM + ABaseAMD64 + ABasePPC64 + ABaseARM64 + ABaseMIPS64 + ABaseS390X + + AllowedOpCodes = 1 << 10 // The number of opcodes available for any given architecture. + AMask = AllowedOpCodes - 1 // AND with this to use the opcode as an array index. +) + +// An LSym is the sort of symbol that is written to an object file. +type LSym struct { + Name string + Type SymKind + Version int16 + Attribute + + RefIdx int // Index of this symbol in the symbol reference list. + Args int32 + Locals int32 + Size int64 + Gotype *LSym + Autom *Auto + Text *Prog + Pcln *Pcln + P []byte + R []Reloc +} + +// Attribute is a set of symbol attributes. +type Attribute int16 + +const ( + AttrDuplicateOK Attribute = 1 << iota + AttrCFunc + AttrNoSplit + AttrLeaf + AttrSeenGlobl + AttrOnList + + // MakeTypelink means that the type should have an entry in the typelink table. + AttrMakeTypelink + + // ReflectMethod means the function may call reflect.Type.Method or + // reflect.Type.MethodByName. Matching is imprecise (as reflect.Type + // can be used through a custom interface), so ReflectMethod may be + // set in some cases when the reflect package is not called. + // + // Used by the linker to determine what methods can be pruned. + AttrReflectMethod + + // Local means make the symbol local even when compiling Go code to reference Go + // symbols in other shared libraries, as in this mode symbols are global by + // default. "local" here means in the sense of the dynamic linker, i.e. not + // visible outside of the module (shared library or executable) that contains its + // definition. (When not compiling to support Go shared libraries, all symbols are + // local in this sense unless there is a cgo_export_* directive). + AttrLocal +) + +func (a Attribute) DuplicateOK() bool { return a&AttrDuplicateOK != 0 } +func (a Attribute) MakeTypelink() bool { return a&AttrMakeTypelink != 0 } +func (a Attribute) CFunc() bool { return a&AttrCFunc != 0 } +func (a Attribute) NoSplit() bool { return a&AttrNoSplit != 0 } +func (a Attribute) Leaf() bool { return a&AttrLeaf != 0 } +func (a Attribute) SeenGlobl() bool { return a&AttrSeenGlobl != 0 } +func (a Attribute) OnList() bool { return a&AttrOnList != 0 } +func (a Attribute) ReflectMethod() bool { return a&AttrReflectMethod != 0 } +func (a Attribute) Local() bool { return a&AttrLocal != 0 } + +func (a *Attribute) Set(flag Attribute, value bool) { + if value { + *a |= flag + } else { + *a &^= flag + } +} + +// The compiler needs LSym to satisfy fmt.Stringer, because it stores +// an LSym in ssa.ExternSymbol. +func (s *LSym) String() string { + return s.Name +} + +type Pcln struct { + Pcsp Pcdata + Pcfile Pcdata + Pcline Pcdata + Pcdata []Pcdata + Funcdata []*LSym + Funcdataoff []int64 + File []*LSym + Lastfile *LSym + Lastindex int +} + +// A SymKind describes the kind of memory represented by a symbol. +type SymKind int16 + +// Defined SymKind values. +// +// TODO(rsc): Give idiomatic Go names. +// TODO(rsc): Reduce the number of symbol types in the object files. +//go:generate stringer -type=SymKind +const ( + Sxxx SymKind = iota + STEXT + SELFRXSECT + + // Read-only sections. + STYPE + SSTRING + SGOSTRING + SGOFUNC + SGCBITS + SRODATA + SFUNCTAB + + SELFROSECT + SMACHOPLT + + // Read-only sections with relocations. + // + // Types STYPE-SFUNCTAB above are written to the .rodata section by default. + // When linking a shared object, some conceptually "read only" types need to + // be written to by relocations and putting them in a section called + // ".rodata" interacts poorly with the system linkers. The GNU linkers + // support this situation by arranging for sections of the name + // ".data.rel.ro.XXX" to be mprotected read only by the dynamic linker after + // relocations have applied, so when the Go linker is creating a shared + // object it checks all objects of the above types and bumps any object that + // has a relocation to it to the corresponding type below, which are then + // written to sections with appropriate magic names. + STYPERELRO + SSTRINGRELRO + SGOSTRINGRELRO + SGOFUNCRELRO + SGCBITSRELRO + SRODATARELRO + SFUNCTABRELRO + + // Part of .data.rel.ro if it exists, otherwise part of .rodata. + STYPELINK + SITABLINK + SSYMTAB + SPCLNTAB + + // Writable sections. + SELFSECT + SMACHO + SMACHOGOT + SWINDOWS + SELFGOT + SNOPTRDATA + SINITARR + SDATA + SBSS + SNOPTRBSS + STLSBSS + SXREF + SMACHOSYMSTR + SMACHOSYMTAB + SMACHOINDIRECTPLT + SMACHOINDIRECTGOT + SFILE + SFILEPATH + SCONST + SDYNIMPORT + SHOSTOBJ + SDWARFSECT + SDWARFINFO + SSUB = SymKind(1 << 8) + SMASK = SymKind(SSUB - 1) + SHIDDEN = SymKind(1 << 9) + SCONTAINER = SymKind(1 << 10) // has a sub-symbol +) + +// ReadOnly are the symbol kinds that form read-only sections. In some +// cases, if they will require relocations, they are transformed into +// rel-ro sections using RelROMap. +var ReadOnly = []SymKind{ + STYPE, + SSTRING, + SGOSTRING, + SGOFUNC, + SGCBITS, + SRODATA, + SFUNCTAB, +} + +// RelROMap describes the transformation of read-only symbols to rel-ro +// symbols. +var RelROMap = map[SymKind]SymKind{ + STYPE: STYPERELRO, + SSTRING: SSTRINGRELRO, + SGOSTRING: SGOSTRINGRELRO, + SGOFUNC: SGOFUNCRELRO, + SGCBITS: SGCBITSRELRO, + SRODATA: SRODATARELRO, + SFUNCTAB: SFUNCTABRELRO, +} + +type Reloc struct { + Off int32 + Siz uint8 + Type RelocType + Add int64 + Sym *LSym +} + +type RelocType int32 + +//go:generate stringer -type=RelocType +const ( + R_ADDR RelocType = 1 + iota + // R_ADDRPOWER relocates a pair of "D-form" instructions (instructions with 16-bit + // immediates in the low half of the instruction word), usually addis followed by + // another add or a load, inserting the "high adjusted" 16 bits of the address of + // the referenced symbol into the immediate field of the first instruction and the + // low 16 bits into that of the second instruction. + R_ADDRPOWER + // R_ADDRARM64 relocates an adrp, add pair to compute the address of the + // referenced symbol. + R_ADDRARM64 + // R_ADDRMIPS (only used on mips64) resolves to the low 16 bits of an external + // address, by encoding it into the instruction. + R_ADDRMIPS + // R_ADDROFF resolves to a 32-bit offset from the beginning of the section + // holding the data being relocated to the referenced symbol. + R_ADDROFF + R_SIZE + R_CALL + R_CALLARM + R_CALLARM64 + R_CALLIND + R_CALLPOWER + // R_CALLMIPS (only used on mips64) resolves to non-PC-relative target address + // of a CALL (JAL) instruction, by encoding the address into the instruction. + R_CALLMIPS + R_CONST + R_PCREL + // R_TLS_LE, used on 386, amd64, and ARM, resolves to the offset of the + // thread-local symbol from the thread local base and is used to implement the + // "local exec" model for tls access (r.Sym is not set on intel platforms but is + // set to a TLS symbol -- runtime.tlsg -- in the linker when externally linking). + R_TLS_LE + // R_TLS_IE, used 386, amd64, and ARM resolves to the PC-relative offset to a GOT + // slot containing the offset from the thread-local symbol from the thread local + // base and is used to implemented the "initial exec" model for tls access (r.Sym + // is not set on intel platforms but is set to a TLS symbol -- runtime.tlsg -- in + // the linker when externally linking). + R_TLS_IE + R_GOTOFF + R_PLT0 + R_PLT1 + R_PLT2 + R_USEFIELD + // R_USETYPE resolves to an *rtype, but no relocation is created. The + // linker uses this as a signal that the pointed-to type information + // should be linked into the final binary, even if there are no other + // direct references. (This is used for types reachable by reflection.) + R_USETYPE + // R_METHODOFF resolves to a 32-bit offset from the beginning of the section + // holding the data being relocated to the referenced symbol. + // It is a variant of R_ADDROFF used when linking from the uncommonType of a + // *rtype, and may be set to zero by the linker if it determines the method + // text is unreachable by the linked program. + R_METHODOFF + R_POWER_TOC + R_GOTPCREL + // R_JMPMIPS (only used on mips64) resolves to non-PC-relative target address + // of a JMP instruction, by encoding the address into the instruction. + // The stack nosplit check ignores this since it is not a function call. + R_JMPMIPS + // R_DWARFREF resolves to the offset of the symbol from its section. + R_DWARFREF + + // Platform dependent relocations. Architectures with fixed width instructions + // have the inherent issue that a 32-bit (or 64-bit!) displacement cannot be + // stuffed into a 32-bit instruction, so an address needs to be spread across + // several instructions, and in turn this requires a sequence of relocations, each + // updating a part of an instruction. This leads to relocation codes that are + // inherently processor specific. + + // Arm64. + + // Set a MOV[NZ] immediate field to bits [15:0] of the offset from the thread + // local base to the thread local variable defined by the referenced (thread + // local) symbol. Error if the offset does not fit into 16 bits. + R_ARM64_TLS_LE + + // Relocates an ADRP; LD64 instruction sequence to load the offset between + // the thread local base and the thread local variable defined by the + // referenced (thread local) symbol from the GOT. + R_ARM64_TLS_IE + + // R_ARM64_GOTPCREL relocates an adrp, ld64 pair to compute the address of the GOT + // slot of the referenced symbol. + R_ARM64_GOTPCREL + + // PPC64. + + // R_POWER_TLS_LE is used to implement the "local exec" model for tls + // access. It resolves to the offset of the thread-local symbol from the + // thread pointer (R13) and inserts this value into the low 16 bits of an + // instruction word. + R_POWER_TLS_LE + + // R_POWER_TLS_IE is used to implement the "initial exec" model for tls access. It + // relocates a D-form, DS-form instruction sequence like R_ADDRPOWER_DS. It + // inserts to the offset of GOT slot for the thread-local symbol from the TOC (the + // GOT slot is filled by the dynamic linker with the offset of the thread-local + // symbol from the thread pointer (R13)). + R_POWER_TLS_IE + + // R_POWER_TLS marks an X-form instruction such as "MOVD 0(R13)(R31*1), g" as + // accessing a particular thread-local symbol. It does not affect code generation + // but is used by the system linker when relaxing "initial exec" model code to + // "local exec" model code. + R_POWER_TLS + + // R_ADDRPOWER_DS is similar to R_ADDRPOWER above, but assumes the second + // instruction is a "DS-form" instruction, which has an immediate field occupying + // bits [15:2] of the instruction word. Bits [15:2] of the address of the + // relocated symbol are inserted into this field; it is an error if the last two + // bits of the address are not 0. + R_ADDRPOWER_DS + + // R_ADDRPOWER_PCREL relocates a D-form, DS-form instruction sequence like + // R_ADDRPOWER_DS but inserts the offset of the GOT slot for the referenced symbol + // from the TOC rather than the symbol's address. + R_ADDRPOWER_GOT + + // R_ADDRPOWER_PCREL relocates two D-form instructions like R_ADDRPOWER, but + // inserts the displacement from the place being relocated to the address of the + // the relocated symbol instead of just its address. + R_ADDRPOWER_PCREL + + // R_ADDRPOWER_TOCREL relocates two D-form instructions like R_ADDRPOWER, but + // inserts the offset from the TOC to the address of the the relocated symbol + // rather than the symbol's address. + R_ADDRPOWER_TOCREL + + // R_ADDRPOWER_TOCREL relocates a D-form, DS-form instruction sequence like + // R_ADDRPOWER_DS but inserts the offset from the TOC to the address of the the + // relocated symbol rather than the symbol's address. + R_ADDRPOWER_TOCREL_DS + + // R_PCRELDBL relocates s390x 2-byte aligned PC-relative addresses. + // TODO(mundaym): remove once variants can be serialized - see issue 14218. + R_PCRELDBL + + // R_ADDRMIPSU (only used on mips64) resolves to the sign-adjusted "upper" 16 + // bits (bit 16-31) of an external address, by encoding it into the instruction. + R_ADDRMIPSU + // R_ADDRMIPSTLS (only used on mips64) resolves to the low 16 bits of a TLS + // address (offset from thread pointer), by encoding it into the instruction. + R_ADDRMIPSTLS +) + +// IsDirectJump returns whether r is a relocation for a direct jump. +// A direct jump is a CALL or JMP instruction that takes the target address +// as immediate. The address is embedded into the instruction, possibly +// with limited width. +// An indirect jump is a CALL or JMP instruction that takes the target address +// in register or memory. +func (r RelocType) IsDirectJump() bool { + switch r { + case R_CALL, R_CALLARM, R_CALLARM64, R_CALLPOWER, R_CALLMIPS, R_JMPMIPS: + return true + } + return false +} + +type Auto struct { + Asym *LSym + Link *Auto + Aoffset int32 + Name int16 + Gotype *LSym +} + +// Auto.name +const ( + A_AUTO = 1 + iota + A_PARAM +) + +type Pcdata struct { + P []byte +} + +// symbol version, incremented each time a file is loaded. +// version==1 is reserved for savehist. +const ( + HistVersion = 1 +) + +// Link holds the context for writing object code from a compiler +// to be linker input or for reading that input into the linker. +type Link struct { + Headtype HeadType + Arch *LinkArch + Debugasm int32 + Debugvlog int32 + Debugdivmod int32 + Debugpcln int32 + Flag_shared bool + Flag_dynlink bool + Flag_optimize bool + Bso *bufio.Writer + Pathname string + Hash map[SymVer]*LSym + LineHist LineHist + Imports []string + Plists []*Plist + Sym_div *LSym + Sym_divu *LSym + Sym_mod *LSym + Sym_modu *LSym + Plan9privates *LSym + Curp *Prog + Printp *Prog + Blitrl *Prog + Elitrl *Prog + Rexflag int + Vexflag int + Rep int + Repn int + Lock int + Asmode int + AsmBuf AsmBuf // instruction buffer for x86 + Instoffset int64 + Autosize int32 + Armsize int32 + Pc int64 + DiagFunc func(string, ...interface{}) + Mode int + Cursym *LSym + Version int + Errors int + + Framepointer_enabled bool + + // state for writing objects + Text []*LSym + Data []*LSym + + // Cache of Progs + allocIdx int + progs [10000]Prog +} + +func (ctxt *Link) Diag(format string, args ...interface{}) { + ctxt.Errors++ + ctxt.DiagFunc(format, args...) +} + +func (ctxt *Link) Logf(format string, args ...interface{}) { + fmt.Fprintf(ctxt.Bso, format, args...) + ctxt.Bso.Flush() +} + +// The smallest possible offset from the hardware stack pointer to a local +// variable on the stack. Architectures that use a link register save its value +// on the stack in the function prologue and so always have a pointer between +// the hardware stack pointer and the local variable area. +func (ctxt *Link) FixedFrameSize() int64 { + switch ctxt.Arch.Family { + case sys.AMD64, sys.I386: + return 0 + case sys.PPC64: + // PIC code on ppc64le requires 32 bytes of stack, and it's easier to + // just use that much stack always on ppc64x. + return int64(4 * ctxt.Arch.PtrSize) + default: + return int64(ctxt.Arch.PtrSize) + } +} + +type SymVer struct { + Name string + Version int // TODO: make int16 to match LSym.Version? +} + +// LinkArch is the definition of a single architecture. +type LinkArch struct { + *sys.Arch + Preprocess func(*Link, *LSym) + Assemble func(*Link, *LSym) + Follow func(*Link, *LSym) + Progedit func(*Link, *Prog) + UnaryDst map[As]bool // Instruction takes one operand, a destination. +} + +// HeadType is the executable header type. +type HeadType uint8 + +const ( + Hunknown HeadType = iota + Hdarwin + Hdragonfly + Hfreebsd + Hlinux + Hnacl + Hnetbsd + Hopenbsd + Hplan9 + Hsolaris + Hwindows + Hwindowsgui +) + +func (h *HeadType) Set(s string) error { + switch s { + case "darwin": + *h = Hdarwin + case "dragonfly": + *h = Hdragonfly + case "freebsd": + *h = Hfreebsd + case "linux", "android": + *h = Hlinux + case "nacl": + *h = Hnacl + case "netbsd": + *h = Hnetbsd + case "openbsd": + *h = Hopenbsd + case "plan9": + *h = Hplan9 + case "solaris": + *h = Hsolaris + case "windows": + *h = Hwindows + case "windowsgui": + *h = Hwindowsgui + default: + return fmt.Errorf("invalid headtype: %q", s) + } + return nil +} + +func (h *HeadType) String() string { + switch *h { + case Hdarwin: + return "darwin" + case Hdragonfly: + return "dragonfly" + case Hfreebsd: + return "freebsd" + case Hlinux: + return "linux" + case Hnacl: + return "nacl" + case Hnetbsd: + return "netbsd" + case Hopenbsd: + return "openbsd" + case Hplan9: + return "plan9" + case Hsolaris: + return "solaris" + case Hwindows: + return "windows" + case Hwindowsgui: + return "windowsgui" + } + return fmt.Sprintf("HeadType(%d)", *h) +} + +// AsmBuf is a simple buffer to assemble variable-length x86 instructions into. +type AsmBuf struct { + buf [100]byte + off int +} + +// Put1 appends one byte to the end of the buffer. +func (a *AsmBuf) Put1(x byte) { + a.buf[a.off] = x + a.off++ +} + +// Put2 appends two bytes to the end of the buffer. +func (a *AsmBuf) Put2(x, y byte) { + a.buf[a.off+0] = x + a.buf[a.off+1] = y + a.off += 2 +} + +// Put3 appends three bytes to the end of the buffer. +func (a *AsmBuf) Put3(x, y, z byte) { + a.buf[a.off+0] = x + a.buf[a.off+1] = y + a.buf[a.off+2] = z + a.off += 3 +} + +// Put4 appends four bytes to the end of the buffer. +func (a *AsmBuf) Put4(x, y, z, w byte) { + a.buf[a.off+0] = x + a.buf[a.off+1] = y + a.buf[a.off+2] = z + a.buf[a.off+3] = w + a.off += 4 +} + +// PutInt16 writes v into the buffer using little-endian encoding. +func (a *AsmBuf) PutInt16(v int16) { + a.buf[a.off+0] = byte(v) + a.buf[a.off+1] = byte(v >> 8) + a.off += 2 +} + +// PutInt32 writes v into the buffer using little-endian encoding. +func (a *AsmBuf) PutInt32(v int32) { + a.buf[a.off+0] = byte(v) + a.buf[a.off+1] = byte(v >> 8) + a.buf[a.off+2] = byte(v >> 16) + a.buf[a.off+3] = byte(v >> 24) + a.off += 4 +} + +// PutInt64 writes v into the buffer using little-endian encoding. +func (a *AsmBuf) PutInt64(v int64) { + a.buf[a.off+0] = byte(v) + a.buf[a.off+1] = byte(v >> 8) + a.buf[a.off+2] = byte(v >> 16) + a.buf[a.off+3] = byte(v >> 24) + a.buf[a.off+4] = byte(v >> 32) + a.buf[a.off+5] = byte(v >> 40) + a.buf[a.off+6] = byte(v >> 48) + a.buf[a.off+7] = byte(v >> 56) + a.off += 8 +} + +// Put copies b into the buffer. +func (a *AsmBuf) Put(b []byte) { + copy(a.buf[a.off:], b) + a.off += len(b) +} + +// Insert inserts b at offset i. +func (a *AsmBuf) Insert(i int, b byte) { + a.off++ + copy(a.buf[i+1:a.off], a.buf[i:a.off-1]) + a.buf[i] = b +} + +// Last returns the byte at the end of the buffer. +func (a *AsmBuf) Last() byte { return a.buf[a.off-1] } + +// Len returns the length of the buffer. +func (a *AsmBuf) Len() int { return a.off } + +// Bytes returns the contents of the buffer. +func (a *AsmBuf) Bytes() []byte { return a.buf[:a.off] } + +// Reset empties the buffer. +func (a *AsmBuf) Reset() { a.off = 0 } + +// Peek returns the byte at offset i. +func (a *AsmBuf) Peek(i int) byte { return a.buf[i] } |